Buggy code:
public class ANTLR extends Task { private CommandlineJava commandline = new CommandlineJava ( ) ; private File target ; private File outputDirectory ; private File superGrammar ; private boolean html ; private boolean diagnostic ; private boolean trace ; private boolean traceParser ; private boolean traceLexer ; private boolean traceTreeWalker ; private File workingdir = null ; private ByteArrayOutputStream bos = new ByteArrayOutputStream ( ) ; private boolean debug ; private FileUtils fileUtils ; public ANTLR ( ) { } public void setTarget ( File target ) { } public void setOutputdirectory ( File outputDirectory ) { } public void setGlib ( String superGrammar ) { } public void setGlib ( File superGrammar ) { } public void setDebug ( boolean enable ) { } public void setHtml ( boolean enable ) { } public void setDiagnostic ( boolean enable ) { } public void setTrace ( boolean enable ) { } public void setTraceParser ( boolean enable ) { } public void setTraceLexer ( boolean enable ) { } public void setTraceTreeWalker ( boolean enable ) { } public void setFork ( boolean s ) { } public void setDir ( File d ) { } public Path createClasspath ( ) { } public Argument createJvmarg ( ) { } public void init ( ) throws BuildException { } protected void addClasspathEntry ( String resource ) { } public void execute ( ) throws BuildException { validateAttributes ( ) ; File generatedFile = getGeneratedFile ( ) ; boolean targetIsOutOfDate = ( target . lastModified ( ) ) > ( generatedFile . lastModified ( ) ) ; boolean superGrammarIsOutOfDate = ( ( superGrammar ) != null ) && ( ( superGrammar . lastModified ( ) ) > ( generatedFile . lastModified ( ) ) ) ; if ( targetIsOutOfDate || superGrammarIsOutOfDate ) { if ( targetIsOutOfDate ) { log ( ( ( ( "Compiling<seq2seq4repair_space>" + ( target ) ) + "<seq2seq4repair_space>as<seq2seq4repair_space>it<seq2seq4repair_space>is<seq2seq4repair_space>newer<seq2seq4repair_space>than<seq2seq4repair_space>" ) + generatedFile ) , MSG_VERBOSE ) ; } else if ( superGrammarIsOutOfDate ) { log ( ( ( ( ( ( "Compiling<seq2seq4repair_space>" + ( target ) ) + "<seq2seq4repair_space>as<seq2seq4repair_space>" ) + ( superGrammar ) ) + "<seq2seq4repair_space>is<seq2seq4repair_space>newer<seq2seq4repair_space>than<seq2seq4repair_space>" ) + generatedFile ) , MSG_VERBOSE ) ; } populateAttributes ( ) ; commandline . createArgument ( ) . setValue ( target . toString ( ) ) ; log ( commandline . describeCommand ( ) , MSG_VERBOSE ) ; int err = run ( commandline . getCommandline ( ) ) ; <START_BUG> if ( Execute . isFailure ( err ) ) { <END_BUG> throw new BuildException ( ( "ANTLR<seq2seq4repair_space>returned:<seq2seq4repair_space>" + err ) , getLocation ( ) ) ; } else { String output = bos . toString ( ) ; if ( ( output . indexOf ( "error:" ) ) > ( - 1 ) ) { throw new BuildException ( ( "ANTLR<seq2seq4repair_space>signaled<seq2seq4repair_space>an<seq2seq4repair_space>error:<seq2seq4repair_space>" + output ) , getLocation ( ) ) ; } } } else { log ( ( ( "Skipped<seq2seq4repair_space>grammar<seq2seq4repair_space>file.<seq2seq4repair_space>Generated<seq2seq4repair_space>file<seq2seq4repair_space>" + generatedFile ) + "is<seq2seq4repair_space>newer." ) , MSG_VERBOSE ) ; } } private void populateAttributes ( ) { } private void validateAttributes ( ) throws BuildException { } private File getGeneratedFile ( ) throws BuildException { } private int run ( String [ ] command ) throws BuildException { } protected boolean is272 ( ) { } }

Fix:
if ( err != 0 ) {